pybmoore 1.3.0

Python/Cython Boyer-Moore string-search algorithm

pybmoore

Python/Cython implementation of Boyer-Moore string-search algorithm.

Installing

Install and update using pip:

pip install pybmoore

notice: gcc must be available on the system.

Usage

Single term

The search method in the pybmoore module will return a list of tuples with all occurrences, where the tuple have the initial and final position. For example:

import pybmoore

TEXT = "The Boyer–Moore string-search algorithm is an efficient string-searching algorithm that is the standard benchmark for practical string-search literature."

matches = pybmoore.search('string', TEXT)
print(f"Occurrences: {len(matches)}")
# output: Occurrences: 3

print(matches)
# output: [(16, 22), (56, 62), (128, 134)]

for x, y in matches:
    print(f"({x},{y}) - {TEXT[x:y]}")

notice: search method it's case sensitive.

import pybmoore

TEXT = "The algorithm preprocesses the string being searched for (the pattern), but not the string being searched in (the text). It is thus well-suited for applications in which the pattern is much shorter than the text or where it persists across multiple searches."

pybmoore.search('algorithm', TEXT)
# output: [(4, 13)]

pybmoore.search('Algorithm', TEXT)
# output: []

Multiple terms

import pybmoore

TEXT = "The Boyer-Moore algorithm searches for occurrences of P in T by performing explicit character comparisons at different alignments. Instead of a brute-force search of all alignments (of which there are m − n + 1, Boyer-Moore uses information gained by preprocessing P to skip as many alignments as possible."

pybmoore.search(['brute-force', 'Boyer-Moore'], TEXT)
print(matches)
# output: {'brute-force': [(144, 155)], 'Boyer-Moore': [(4, 15), (212, 223)]}

Development

To build pybmoore locally first install requirements-dev.txt dependencies and run:

make build # without Cython

make build USE_CYTHON=1 # with Cython

in some cases it's necesary run make clean before make build.

Type make in the command line to see all available targets.

Links

• License: Apache License
• Code: https://github.com/amenezes/pybmoore
• Issue tracker: https://github.com/amenezes/pybmoore/issues